1. Field of the Invention
This invention relates to a method for the production of carboxylic acids. More particularly, this invention relates to the conversion of allyl formate to carboxylic acids including isobutyric acid, n-butyric acid and/or glutaric acid. In particular, the present invention is directed to a process wherein allyl formate is brought into contact with activated carbon in the presence of carbon monoxide, a soluble compound of a group VIII catalyst, a halide promoter and at least a minor amount of water and formic acid whereby the allyl formate is converted with good yield and selectivities to the corresponding carboxylic acids. Isobutyric and n-butyric acids are preferentially formed when the concentration of water and formic acid are comparatively low. Glutaric acid is preferentially formed in the presence of comparatively higher concentrations of water and formic acid. The desired conversion is not obtained in the absence of formic acid. Isobutyric acid, which is a precursor for use in the manufacture of methacrylic acid is the predominant butyric acid isomer.
2. Prior Art
Illing et al. West German patent No. 1,072,979 discloses the isomerization of primary, secondary and tertiary monohydric or polyhydric saturated aliphatic, cycloaliphatic or aryliphatic esters of formic acid to the corresponding carboxylic acids in the presence of a halogen promoted carbonyl-forming metal of the 6th, 7th or 8th group of the Periodic Table in the presence of a support and, preferably, an activator. The activator may be a compound of bismuth, antimony or boron. The catalyst may be applied to a support such as charcoal, extruded silica, kieselguhr, zeolites, aluminum, pumice or bentonite. The reaction is preferably conducted in the presence of inert gas such as carbon monoxide, carbon dioxide or nitrogen.
Ray European patent application No. 0060695 published Sep. 22, 1982, is directed to the coproduction of formic acid in C.sub.2 to C.sub.10 monocarboxylic acids by the aqueous carbonylation of C.sub.1 to C.sub.9 alkyl formates. The carbonylation is conducted in the presence of a halogen promoted supported or unsupported Group VIII noble metal (e.g., rhodium).
Woodhouse U.S. Pat. No. 1,946,254 discloses the preparation of monocarboxylic acids by passing a vaporized aliphatic monohydroxy alcohol, carbon monoxide and a halogen over activated carbon.
Wakamatsu et al. in U.S. Pat. No. 3,798,267 discloses the preparation of formic acid by contacting methyl formate with activated carbon in the presence of a halide promoter and carbon monoxide.
Antoniades U.S. Pat. No. 4,194,056 also discloses a process for the preparation of formic acid from methyl formate. In accordance with the Antoniades process, the methyl formate is brought into contact with a soluble rhodium salt catalyst in the presence of carbon monoxide and a halogen promoter.
Isogai U.S. Pat. No. 3,839,426 is more broadly directed to the preparation of organic carboxylic acids from formic acid esters, such as vinyl formate (Example 36) by contacting the formic acid ester with a group VIII or group IIb catalyst in the presence of carbon monoxide.
French patent No. 2,030,118 discloses a process wherein carboxylic acids, especially formic acid, are produced from methanol by reacting methanol and carbon monoxide over a solid activated carbon bed at a temperature of from 200.degree. to about 500.degree. C. and a pressure of about 100 to about 3000 psi (7-210 Kg/cm.sup.2) using a halogen promoter which is either dispersed on the carbon bed or incorporated as a component of the catalyst system.
Copending coassigned U.S. patent application Ser. No. 478,830 filed Mar. 25, 1983, now abandoned, in the name of John M. Larkin and entitled "A Process for Alkanol Carbonylation to Carboxylic Acids Using the Novel Combination of Catalyst and Carbon Bed Components" discloses a process wherein an alkanol together with a halide promoter and a low concentration of a soluble metal catalyst is passed over a carbon bed in the presence of carbon monoxide.
Copending coassigned U.S. patent application Ser. No. 478,829 filed Mar. 25, 1983, now abandoned, in the name of John M. Larkin and Roger G. Duranleau and entitled "A Process for Producing Carboxylic Acids by Carbonylation of Alkanols Over a Carbon Catalyst" discloses a process wherein an alkanol and a halide promoter are passed over a carbon bed contained in a nickel or cobalt alloy reactor in the presence of carbon monoxide.